1. Field of Invention
The present invention relates to a water vapor permeable and waterproof polyether ester membrane that is pigmented with carbon particles, as well as its manufacture and use.
2. Description of Related Art
The manufacture of films from polymers that contain carbon particles and are intended to be waterproof and water vapor permeable is known.
Films of this type are disclosed, for example, in the European patent specification EP-A2-0214859. The films are microporous, contain 20 to 40% of a filler that can, among other things, be carbon (e.g., carbon black). The films are stretched and the particle size of the deposited carbon particles is about 0.05 to 50 .mu.m. However, it has been discovered that these films are not completely waterproof after all.
As disclosed in DE-A1-4003765, a water vapor permeable and waterproof material consisting of a carrier material onto which a membrane has been applied, and which has no pores, has been manufactured. Adsorber particles are made to adhere to this membrane. The adsorber particles can be activated carbon, which, for example, has an average diameter of 0.1 to 1 mm.
However, membranes or films of this kind have a series of disadvantages. First, the distribution of the carbon particles in the polymer leaves much to be desired. Second, such pigmented films or membranes do not achieve certain properties that various applications require, such as high ultraviolet ("UV") stability and favorable infrared ("IR") reflectance properties.
Thus, although a whole series of films and membranes pigmented with carbon is known, there remains a need for improved water vapor permeable and waterproof membranes and processes by which such membranes can advantageously be manufactured.
The object of the present invention is therefore to provide a water vapor permeable, waterproof membrane that is very homogeneous, has good UV stabilities and elevated IR reflectance, and that can be put to a variety of uses.